Endoscopy (e.g., laparoscopy, thoracoscopy, arthroscopy, etc.) is a form of surgery that involves visualizing the interior of the body using an illuminating optical instrument, an endoscope. The endoscope and other surgical instruments are introduced into the body through small puncture orifices.
Endoscopic procedures typically are commenced by using a device known as a trocar. The trocar comprises a cannula or trocar sleeve (a hollow sheath or sleeve with a central lumen) and a sharp obturator received in the cannula. The trocar is used to penetrate the abdominal wall or chest. The obturator is withdrawn from the cannula after the intra-abdominal end of the trocar is in the abdominal cavity, and the cannula remains in the abdominal wall throughout the surgical procedure, allowing the introduction of surgical instruments. Trocars are available in different sizes, as are cannulae, to accommodate various instruments.
Endoscopy, in the form of laparoscopy, traditionally has been used almost exclusively for gynecological surgery. However, physicians specializing in other fields have begun to recognize the diagnostic and operative value of endoscopy.
The advantages of endoscopic surgery include: procedures may be performed on an outpatient basis; surgeons are given the opportunity to view intra-abdominal viscera without performing a laparotomy, a large incision of the abdominal wall; small puncture ports or wounds are created rather than large incisions, lessening trauma; incision sites for laparotomies may be determined accurately; patient and insurer medical costs are reduced by shorter hospital stays; and postoperative patient discomfort, with recovery times measured in days as opposed to weeks, is lessened.
Thus, there is a substantial interest in and need for providing task specific surgical instruments particularly adapted to general surgical procedures now being performed endoscopically. Because endoscopy, particularly laparoscopy, is an evolving specialty within the field of general surgery, currently available instruments inadequately meet the needs of laparoscopic surgeons.
Heretofore, surgical instruments designed specifically for endoscopic procedures generally take the form of a specialized implement (hereinafter called an end effector) fixedly attached to the distal end of a rigid shaft, with an operating linkage mechanism internal or external to that shaft. A handle attached to the opposite, proximal end of the shaft usually has an associated manual mechanism for operating the end effector, and may have a second manual mechanism to rotate the shaft and end effector. Generally, in order to fit through the small diameter ports or incisions, an instrument is designed for a single, dedicated, specialized purpose. Ideally, a surgeon selects instruments according to his preferences and according to the procedure at hand. However, because of the costs involved with using additional instruments and the time associated with removing one and inserting another, a surgeon is inclined to make do with the instruments of initial use even though another instrument may be more suitable for the immediate task.
Another significant limitation in the design of current instruments is that to reposition the end effector, a surgeon must use both hands; one hand to manipulate manually a thumbwheel or knob to rotate the shaft (and end effector), and one to hold the instrument. This means that a second instrument in use has to be released, or the assisting physician or nurse has to provide help.
U.S. Pat. Nos. 4,986,825 (to Bays et al.) and 5,133,736 (to Bales, Jr. et al.) disclose surgical instruments including end effectors, e.g., scissors, dissectors, cutting jaws, etc., attached to tubular members. However, neither patent discloses or teaches how to conveniently reposition an end effector relative to the rest of an instrument while the instrument is in use.
An even greater limitation, and problem, stems from the fact that end effectors are fixedly attached to the distal end of the instrument shaft which passes through the endoscopic port. Because of this limitation in instrument design, correct placement of the port is crucial for direct access to the subject tissue or internal structure. Frequently, due to the fixed position of the end effector relative to the instrument shaft, additional laparoscopic pods or incisions must be created to allow a suitable instrument angle and access to the tissue of interest.